PDP-11/53+ Jumpers - test-drb@ccmp.vtda.org

6 Jun 2001

I have a 11/73 and several 11/23s (some with clock mods for speed)
so I'm aware of what I said.  MOST early 11/53 boxen actually had 11/23B
cpu cards (M8189).

Oh yes, I do have a very fast 11/23B as a result of a modded clock.

Allison

-----Original Message-----
From: Jonathan Engdahl &lt;engdahl(a)cle.ab.com&gt;
To: classiccmp(a)classiccmp.org &lt;classiccmp(a)classiccmp.org&gt;
Date: Wednesday, June 06, 2001 2:45 PM
Subject: RE: PDP-11/53+ Jumpers

...
 The M7554 has a Qbus on the A-B connector, and nothing
but grant jumpers and
...
 power on the C-D connector.

I don't know anything about 11/73's, but the first thing I noticed when I
...
 got the 11/53 to boot was "Whoa! -- this thing is
a lot faster than an
11/23".

Maybe Allison had better go looking for someone with a very fast "11/23"
and
...
 get his CPU board back!

--
Jonathan Engdahl Rockwell Automation
Principal Research Engineer 24800 Tungsten Road
Advanced Technology Euclid, OH 44117, USA
Euclid Labs engdahl(a)cle.ab.com  216-266-6409

> -----Original Message-----
> From: owner-classiccmp(a)classiccmp.org
> [mailto:owner-classiccmp@classiccmp.org]On Behalf Of Pete Turnbull
> Sent: Wednesday, June 06, 2001 3:22 AM
> To: classiccmp
> Subject: Re: PDP-11/53+ Jumpers
>
>
> On Jun 5, 22:37, ajp166 wrote:
> > Isn't the 11/53 the box name and the cpu being either an 11/73
> > or 11/23B?  All the 11/53s I've seen had 11/23B cpus (M8189).
>
> No, an 11/53 processor is an M7554, which is a quad board with J11, half a
...
 > meg of memory, 2 SLUs, bootstrap, etc.  It's
rather like an
> 11/73B but with
> added memory (and no PMI capability, I think).  It was designed as a low
...
   end system,
and IIRC it's slightly slower than an 11/73.

 If you saw 11/53 BA23's with 11/23's in them, someone swapped the
 cards, or
 swapped the labels.

 --
 Pete Peter Turnbull
 Network Manager
 University of York